This invention relates to animal feeds, and more particularly to an improved animal feed composition and method of compounding animal feed utilizing a carboxylic containing compound as a binder.
The manufacture of animal feeds depends heavily on the use of low cost by-product ingredients. These ingredients are frequently dusty, unpalatable, of low density, and have inadequate nutrient profile. To correct these shortcomings, ingredients are combined into a mixture to provide adequate energy and protein, and supplemented with the necessary vitamins, minerals, and amino acids to meet the nutrient requirements of the animals. These mixtures are then typically processed via known extrusion and/or compaction techniques to form pellets, blocks or briquettes in order to eliminate ingredient segregation, increase bulk density, reduce dust, mask unpalatable ingredients, and reduce wastage. All of these benefits are dependent upon the pellet, block or briquette maintaining its physical integrity.
Since feed formulations are typically dictated by the cost and availability of byproduct ingredients, it is not always possible to produce durable pellets, blocks or briquettes. Some ingredients such as animal fat, meat meal, ground corn, and oat hulls, have poor binding qualities and may even be antagonistic to binding. When such ingredients are used a binder is often included to insure that a durable pellet, block or briquette is produced. Typically, lignosulfonate, a naturally occurring polymer generated via sulfite digestion of wood in the manufacture of pulp and paper, is applied to the feed at a rate of 25 to 50 lbs. per ton of feed. This level of application reduces fines from 25% to 60% versus pellets, blocks or briquettes containing no binder.
Lignosulfonates contain no protein and little metabolizable energy and are therefore unpopular in nutritionally dense formulations, e.g. poultry feeds and pig starter feeds, due to the diluting effect they have on the feed. In addition, lignosulfonates are thought to be unpalatable to piglets and young pigs, limiting their use in pig starter feeds. Manufacturers of poultry feeds and pig starter feeds would therefore benefit from a binder which could perform as well as a lignosulfonate but could be applied at a lower inclusion rate, namely, at 5 pounds per ton of feed or less. Such a binder would reduce the diluting effect of the binder, and correspondingly increase the available nutrition to be supplied to the animal in its feed.
So called "low inclusion" binders have been introduced to the feed industry to fill this niche. These include Nutraflex, a protein colloid manufactured by Swift Co., Hercule's Cellulose Gum, a carboxymethyl cellulose manufactured by Hercules Inc., Production Aid ES, a lignosulfonate-starch blend manufactured by Cravac Industries, and Basfin, a urea-formaldehyde manufactured by BASF. Each of these products provides some improvement in pellet, block or briquette quality, but none can produce a 25% to 60% reduction in fines as occurs when lignosulfonates are used at their recommended levels.
In addition to the above noted "low inclusion" binders, there are several disclosures relating to copolymers of lignosulfonate and acrylic compounds useful for various applications. For example, U.S. Pat. No. 4,374,738 discloses a water-based drilling mud composition which comprises an aqueous disperson of clay material and a graft copolymer of lignosulfonate and an acrylic compound including acrylic acid, acrylonitrile and acrylamide. In U.S. Pat. No. 4,276,077, a method is revealed for improving a soil structure by stabilization of aggregates obtained from crude lignosulfonate and a monomer selected from among acrylonitrile, vinyl acetate, acrylamide or combinations thereof. Soviet Union Patent No. 1,168,515 (July 23, 1985) discloses the use of a copolymer of lignosulfonate and (meth)acrylic acid for inhibiting the deposit of inorganic salts. A study of graft copolymerization of lignosulfonate acrylic compounds was reported in the Journal of Applied Polymer Science, Vol. 25 : 2211-2220 (1980). These cited disclosures, however, failed to recognize the use of a copolymer of lignosulfonate and a carboxylic containing compound such as an acrylic polymer as a binder in animal feeds.
It is therefore an object of this invention to provide an effective binder for animal feed compositions.
It is another object of this invention to provide an animal feed binder obtained from sulfonated lignin materials.
It is still another object of this invention to provide a binder which, when mixed with animal feed at 5 pounds per ton of feed or less, will reduce fines by at least about 20% to about 25% versus untreated feed.
Other objects and features of this invention may be evident in the following detailed disclosure.